/************************************************************************
  Scheme interpreter
  
  Copyright (C) 2010 Marioly Garza 

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as
  published by the Free Software Foundation, either version 3 of the
  License, or (at your option) any later version.
  
  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.
  
  You should have received a copy of the GNU Lesser General Public
  License along with this program. If not, see
  <http://www.gnu.org/licenses/>.

************************************************************************/

#include "environment.h"
#include <iostream>

environment::environment(std::list<object*> vars, std::list<object*> vals, environment *parent)
{
    if (!vars.empty() && !vals.empty()) {
        extend(vars, vals);
    }
    this->parent = parent;
}

object* environment::lookup(std::string name)
{
    if (table[name] == NULL)
    {
        if (parent != NULL)
            return parent->lookup(name);
        else
            throw scheme_exception(util::format("the name '%s' does not exist in the current context", name.c_str()));
    }
    else
    {
        return table[name];
    }
}

void environment::extend(std::string var, object* val)
{
    table[var] = val;
}

void environment::extend(std::list<object*> vars, std::list<object*> vals)
{
    while (!vars.empty() && !vals.empty()) {
        sstring* k = (sstring*)vars.front();
        sstring* v = (sstring*)vals.front();
        table[k->to_string()] = v;
        vars.pop_front();
        vals.pop_front();
    }
}
